>I found a support page that may apply to your machine: https://www.asus.com/us/Laptops/ASUS-VivoBook-S15-S510UA/HelpDesk_Download/
>
>If that's the case I would look at these specific updates, if applicable. If you're unsure you could try to install them, they are generally very good about not installing if the same, or a newer one, is already present:
>
>- BIOS
>- Intel Rapid Storage Technology driver (under "Others")
>- Chipset
>
>If those don't help I don't know what else to suggest. Your laptop may have built-in diagnostics accessible from the boot menu, you could try running that. Or, in Device Manager you could get the make/model of the SSD, and download and run a manufacturer's diagnostic if available.
>
>Did you receive the machine with the SSD already installed, or is that an upgrade you did later? If you upgraded it yourself, exactly how did you do it? Did you use any imaging software such as Acronis which might still be running in Windows on the new SSD?

Thanks for the ASUS page, I'll look into it.

I installed the SSD myself. I used PCMover to move everything from my old PC (HP). That seems to have worked quite well - almost all programs run fine on the new ASUS PC.